Simplify Li-Ion battery backup systems

The LTC4040 uses an on-chip bidirectional synchronous converter to provide high efficiency battery charging as well as high current, high efficiency backup power. When external power is available, the system operates as a step-down battery charger for single-cell Li-Ion or LiFePO4 batteries while giving preference to the system load. When the input supply drops below the adjustable power-fail input threshold, the device operates as a step-up regulator capable of delivering up to 2.5A to the system output from the backup battery. During a power fail event, the system’s PowerPath control provides reverse blocking and a seamless switchover between input power and backup power. Typical applications for the LTC4040 include fleet and asset tracking, automotive GPS data loggers, automotive telematics systems, toll collection systems, security systems, communications systems, industrial backup and USB-powered devices.

The device also includes optional overvoltage protection, which protects the IC from input voltages greater than 60V with an external FET. Its adjustable input current limit function enables operation from a current limited source while prioritising system load current over battery charge current. An external disconnect switch isolates the primary input supply from the system during backup. The system’s 2.5A battery charger provides eight selectable charge voltages optimised for Li-Ion and LiFePO4 batteries. The LTC4040 also includes input current monitoring, an input power loss indicator and a system power loss indicator.

The LTC4040 is housed in a low profile 24-pin 4mx5mm QFN package with backside metal pad for outstanding thermal performance. The system operates from -40 to +125°C, in both E and I grades. The device is in stock, and 1,000-piece pricing starts at $2.90 each for the E grade.